PhpStorm 2016.3 Help

Configuring Include Paths

Include paths are used for code completion and reference resolution in some functions/methods that use file paths as arguments
(for example, require() or include()).
You also need to configure PEAR as an include path to run the PHPUnit test framework from it
when the Load from include path option is chosen on the PHPUnit page of the Settings / Preferences Dialog.

To configure include paths:

Open the Settings / Preferences Dialog by pressing Ctrl+Alt+S or by choosing File | Settings for Windows and Linux or
PhpStorm | Preferences for OS X,
and
click PHP under Languages&Frameworks.